Astronomers have found a pulsating, dead star beaming with the energy of about 10 million suns. This is the brightest pulsar – a dense stellar remnant left over from a supernova explosion – ever recorded. The discovery was made with NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR.

The galaxy Messier 82 (M82) is seen here in two different lights. A visible-light view from NASA's Hubble Space Telescope is at left, and an X-ray view from NASA's Chandra X-ray Observatory is at right.

This artist's illustration shows a black hole (center of disk) with matter from a massive companion star falling onto it. Objects like this are thought to make up the "ultraluminous X-ray source," or ULX, population, but recently one ULX was found to be a dead star called a pulsar, not a black hole.

This animation shows a neutron star -- the core of a star that exploded in a massive supernova. This particular neutron star is known as a pulsar because it sends out rotating beams of X-rays that sweep past Earth like lighthouse beacons.